Oxygen producing canister



Oct. 1, 1968 w. K. LEMCKE ETAL 3,403,981

OXYGEN PRODUCING CANISTER Filed Sept. 15, 1965 INVENTORS. WATER K.LEMCKE HANS E. REECK K their 2 arr-02)? United States Patent 3,403,981OXYGEN PRODUCING CANISTER Walter K. Lemcke and Hans E. Reeck, Berlin,Germany,

assignors to Auergesellschaft G.m.b.H., Berlin, Germany, a corporationof Germany Filed Sept. 15, 1965, Ser. No. 487,476 Claims priority,application 1Gig-many, Sept. 22, 1964,

3 Claims. ci. 23-281) ABSTRACT OF THE DISCLOSURE This invention relatesto breathing apparatus canisters, and more particularly to thosecontaining a chemical that absorbs carbon dioxide and generates oxygenwhen contacted with the exhaled breath of the user.

It is well known to use in self-contained, or closed cycle breathingapparatus a canister containing a chemical such as, for example, K0 thatevolves oxygen through the action of carbon dioxide and water containedin exhaled breath. It is important that such canisters not only releaseoxygen in sufficient amounts for breathing, but also capturesubstantially all the exhaled carbon dioxide in order to avoidundesirable stimulation of the breathing process by reinhalation ofcarbon dioxide. Although carbon dioxide is most effectively removed bythin layering of the chemical in the canister, such packing leads tosevere caking of the chemical during use that results in a considerableincrease in resistance to flow through the canister which makesbreathing significantly more difiicult. Heretofore, breathing resistancehas been decreased by placing the chemical on corrugated screens in aparallel or crisscross arrangement, but carbon dioxide is passed by suchcanisters in relatively large amounts.

It is among the objects of this invention to provide a canister of theoxygen-producing type that substantially completely absorbs the carbondioxide from exhaled air and that has a low breathing resistance overthe entire life of the canister.

In accordance with this invention, a breathing apparatus canisterhousing has inlet and outlet openings, and contains layers of granularchemical that will absorb carbon dioxide and generate oxygen whencontacted with exhaled breath disposed transversely to the direction ofair flow through the canister. A plurality of the layers arediscontinuous, having passages or air channels extending therethrough,and are conveniently formed by supporting the granular chemical on ascreen having grooves equal in depth to the layer thickness. Thediscontinuous layers are spaced from each other by a continuous layer ofgranular chemical confined between screens. It is preferred that thelayer adjacent the canister inlet opening be a continuous layer.

A preferred embodiment of the invention is illustrated in theaccompanying drawing, in which the single figure is a side view of ourbreathing apparatus canister with about half of it shown in section.

Referring to the drawing, a conventional metal canister 1, generallycylindrical or oval-shaped, is provided in 3,403,981 Patented Oct. 1,1968 "ice its opposite ends with inlet and outlet openings 2 and 3 thatare preferably at the center of the housing. These openings aresurrounded by tubular extensions 4 that can be connected to hoses thatconduct exhaled air away from the user and deliver purified air andoxygen to him. The canister is also suitable for use in apparatus inwhich both exhaled air and inhaled air pass through the canister; insuch apparatus the inlet opening 2 is connected to a hose leading to abreathing mask and Outlet opening 3 is connected to a breathing bag. Thecanister as shown has six layers, although three may be sufiicient insome cases, while in other cases it may be desirable to have more thansix layers.

The discontinuous layers 5 are formed of granular chemical, such as K0supported on screens 6 having grooves 7 extending the full depth of thelayer so that the unfilled grooves provide an air distribution channelthrough the layer. The sidewalls of the grooves may have protuberances,or dimples, 8 that strengthen the screen and provide for a constantwidth of the grooves. The chemical tends to swell on reaction withexhaled breath, so if necessary, depending on the strength of the screenused, the grooves may be reinforced by spacers, suitably corrugatedscreen inserted into the grooves.

The discontinuous layers are spaced from each other by continuous layers9 of the same granular chemical extending fully across the canister andconfined between a flat lower screen 10 and a flat upper screen 11. Thescreens confining the continuous layer may be formed by attaching theupper parts of the grooved screen together and covering the lower openparts of the groove with pieces of screen. In the preferredconstruction, screens 11 and 6 provide a small air distribution spacebetween the upper surface of the continuous layer and the lower surfaceof the discontinuous layer. If desired, screens 11 and 6 may beseparated by spacers to provide a larger air distribution channel.Preferably, the granules of the continuous layer are larger than thegranules of the discontinuous layer.

It is preferred that the continuous layer adjacent the inlet opening forexhaled breath be a continuous layer and be spaced from the end of thecanister a short distance by a screen 12.

With the canister of this invention, a substantially complete absorptionof carbon dioxide is obtained throughout the time of use, while at thesame time, a low breathing resistance is maintained. The continuouslayers prevent any substantial short circuiting of the exhaled breatharound the granular chemical, while heat occurring during the reaction,the primary cause of caking and high breathing resistance, is dissipatedor conducted off by the screen layers and air spaces in thediscontinuous layer.

According to the provisions of the patent statutes, we have explainedthe principle and mode of practice of our invention and have describedwhat we now consider to represent its best embodiment. However, wedesire to have it understood that, within the scope of the appendedclaims, the invention may be practiced otherwise than as specificallydescribed.

We claim:

1. An oxygen producing canister having opposed inlet and outlet openingsand containing a granular chemical that absorbs carbon dioxide andgenerates oxygen on contact with exhaled breath, a plurality of firstand second layers transverse to said openings and alternately disposedlengthwise of said openings; said first layers each consisting of afirst flat screen, a second flat screen and a first bed of said granularchemical confined therebetween, said second screen being remote fromsaid inlet opening; said second layers each consisting of a thirdReferences Cited screen having grooves therein and a second bed of saidgranular chemical of a depth equal to the depth of said UNITED STATESPATENTS grooves, said second bed being confined between said sec- 2 4 93 7 5 1949 Burggss et 1 3 0nd and third screens; and the granules ofsaid first bed 5 2 913,317 11 1959 Bovard 3 1 being of a larger sizethan the granules of said second bed.

2. A canister according to claim 1 having separator REIGN PATENTS meansspacing said first and third screens. 7 52 323 9/ 1 France 3. A canisteraccording to claim 1 having means reinforcing said grooves againstcollapse. 10 JAMES H. TAYMAN, JR., Primary Examiner.

